TUCSON, Ariz. -- NASA's Phoenix Mars Lander's robotic arm scoop is primed and ready to collect a soil sample from the northern region of Mars to analyze for the presence of water and other possible ingredients.

Scientists and engineers on the mission Friday prepared plans to send Phoenix later in the day that would command the robotic arm to rasp the hard soil in the trench informally named "Snow White," collect the shavings and deliver them to an oven for analysis.

Images received on Earth Friday morning confirmed that the scoop had been cleared of anything collected during previous days' testing. The scoop went through a sequence of moves to dump any remaining material. At the same time, the Thermal and Evolved-Gas Analyzer (TEGA) was successfully prepared for the sample by purging it of any volatile materials.

"The successful completion of these preparatory activities clears the way for our next critical event, delivering the icy soil sample to TEGA," said Doug Ming, of NASA Johnson Space Center, Houston, the team's science lead for today's planning.

The Phoenix mission is led by Peter Smith of the University of Arizona with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions come from the Canadian Space Agency; the University of Neuchatel; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish Meteorological Institute. For more about Phoenix, visit: http://www.nasa.gov/phoenix and http://phoenix.lpl.arizona.edu.